Jar



All@ 9, 1938. M. s. BLACK 2,126,241

` JAR Filed nec. 17, 1954 Mummia/ffm Patented Aug. 9, 1938 UNITED STATES PATENT OFFICE JAB Application December 17, 1934, Serial No. 757,845

7 Claims.

l ment.

It is a still further object of the invention to provide means whereby after actuation of the jar the hammer may be again held inoperative and the spring compressed and the hammer then l released, thereby adapting the jar :for delivering successive jarring blows until the stuck element has been released.

It is a still further object of the invention to deliver a jarring blow while the stuck element is subjected to upward tensile strain.

More particularly it is the object of the invention to provide a jar comprising telescopic elements adapted for incorporation in a drill string, with one of said elements forming an anvil which is adapted to be struck by a hammer which is slidable relative to the telescopic elements and which has an actuating spring, with relative expansion of the telescopic elements, when the lower portion of the drill string is stuck in a well,

subjecting the drill string to upward tensile-strain and at the same time compressing the actuating spring while the hammer is held inoperative. and with said relative expansion of the telescopic elements finally releasing the hammer whereby its compressed spring causes it to deliver a jarring blow against the anvil, and with tensile strain on the drill string'maintained while the jarring blow is being struck.

Further objects of the invention will be readily understood from the following description of the accompanying drawing, in which:

Fig. 1 is a side elevation of the jar, partly in axial section, and incorporated in a drill string ready for the jar to be actuated in the event ofV the lower portion of the drill string being stuck in a well bore.

Fig. 2 is an enlarged axial section through the jar, ready for actuation.

Fig. 3 is an enlarged axial section through the jar, showing the actuating spring compressed and the hammer at the instant of release for operation.

Fig. 4 isa side elevation of the jar, partly in axial section, showing the hammer delivering its jarring blow. f

(el. c55- 27) The jar comprises relatively telescopic elements i-Z adapted for incorporation in a well string such as a string of drill pipe, the vgzier element i being-shown suspended from the upper portion 3 of a drill string by a pin 4, and the lower portion 3a of the drill string being shown suspended from the element 2 by a pin 4a. The telescopic elements may be fixed against relative rotationI as for example by splines 30. A mandrel 5 ls slidable in the telescopic elements and terminates in a hammer 8 which is adapted to strike an anvil 'l which is a xed part of element I. A spring 8 is positioned between the hammer 6 and an internal shoulder 9 of the element I; and latches ill which project upwardly from a sleeve Il which is fixed to the element 2, are adapted to releasably engage the mandrel 5 for holding the hammer 6 inoperative.

A second spring i2 is mounted in an annular recess I3 of sleeve il, betweena shoulder i4 of the recess and a support l5 which is slidable in the recess and which has a dependin'.` extension i6, and when the elements i--Z are relatively telescopically contracted as shown at Fig. 2, the spring l2 seats the support l5 on the upper end of the element 2 withthe extension it depending below a shoulder Ilia on said element, and with a shoulder i'i of the element i, which is adapted to engage the extension it and the shoulder ita, spaced therebclow. V

The latches lli are spring fingers which are received in a restricted bore i8 of element l when the latter is telescopically contracted relative to element 2 as shown at Fig. 2, and the spring i'lngers normally radially contract so that their heads Illa seat in an annular groove i9 which is formed in the mandrel 5, for holding the hammer 6 inoperative.

The restricted bore i8 terminates in an enlarged bore 20, adapted to transversely aline with the latch heads lila when the telescopic element i has been expanded relative to element 2 as shown. at Fig. 3, and the 'lower side of groove I9 preferably tapers as shown at lila and cooperates with corresponding tapering ends illd of the latch heads Illa, so that when the latch heads transversely aline with bore 20, vthe force of spring 8 tending to elevate the mandrel as hereinafter described, causes the latch heads to ride outwardly on tapering surface ia and thereby disengage the groove i9 for releasing the hammer 6 for operative movement to strike the anvil l. As the element i is subsequently telescopically contracted relative to element 2 for resetting the jar, the mandrel 5 is depressed through impingement 55 of anvil 1 against the hammer t until groove Il is again transversely alined with latch heads lia, and at the same time the latch lingers Il slide through the restricted bore I8 for ultimate reengagement of the latch heads with the groove A tapering shoulder 2| preferably connects the bores Il-Zl and cooperates with tapering ends IIb of the latch heads for guiding the latches into the restricted bore Il as the telescopic elements I-2 are relatively contracted for resetting the jar; and a tapering shoulder 22 is preferably formed on the mandrel i just below the groove I9, and cooperates with tapering ends IIIc of the latch heads, for guiding the latter into locking engagement with the groove I9 as the jar is reset.

The spring l is preferably a coil spring, which when telescopic elements I-2 are relatively expanded is compressed between the shoulder 8 and the hammer G as shown at Fig. 3, the hammer being held against movement, as a result of the latch heads Ila engaging the groove I9; and when the bore Il finally disengages the latch heads so that they release the mandrel 5, the compressed spring l drives the hammer upwardly so that it strikes a sharp jarring blow against the anvil 1 as shown at Fig. 4. v

'I'he entire well string is maintained under peak tensile strain during delivery of the jarring blow, with the spring I2 insuring stretch of the well string being taken up and the entire string being subjected to the desired tensile strain before the bore It disengages the latch heads Illa, and in order to provide a spring of the desired tension within the limited space which is available, the spring I2 preferably comprises a plurality of dished resilient annuli I2a, spaced from one another by flat annuii I2b. When the telescopic elements I-2 are relatively expanded the shoulder Il engages the extension Ii of the spring support I5 for elevating the support I5 from the element 2 and thereby compressing the spring I2 by attening out the dished resilient annuli I 2a as shown at Fig. 3, and the tension of the compressed spring arrests relative telescopic expansion of the elements I-2, with the latch heads Illa adjacent the lower end o f the bore il but still engaged by sand bore so that the hammer 6 is still held against delivering its jarring blow, and with the shoulder I1 just about to engage but still clear of the shoulder Iba. The entire well string may thus be subjected to desired tensile strain by upward pull upon the upper portion 3 of the well string. When desired tensile strain has been obtained, the spring I2 yields slightly, permitting the bore I8 to disengage the latch heads Illa for releasing the mandrel 5 and at the same time engaging the shoulder lia by the shoulder I'I, so that the entire well string is maintained under peak tensile strain during delivery of the jarring blow by the hammer 6.

Usual circulation may be maintained through the jar and the drill string in which it is incorporated, .and for this purpose Ithe anvil l and pin 4 are shown provided with a bore 3| communicating with the usual circulation bore of the drill string 3, and mandrel 5 and hammer 8 have a bore 32, preferably terminating at its upper end in a wash pipe 33 which is slidable in bore II, and preferably terminating at its vlower end in a wash pipe 3l which is slidable in the bore l5 of sleeve II. The telescopic element 2 has a bore I6 com- 75 municating with the bore II, and at its lower end the bore 38 opens into the bore 31 of pin la, which in turn communicates with the usual circulation bore of the lower portion la of the drill string.

In operation, assuming the jar incorporated in a drill string as shown at Figs. 1 and 2, with hammer I spaced from anvil 'I and held against movement relative to element I by means of the latches I0; and assuming that the lower portion of the drill string is stuck in the well bore.

The upper portion 3 of the drill string is elevated, thereby expanding telescopic elements I-2-so that the shoulder I'I engages the extension I6 and elevates the support I5 for compressing the spring I2, whereupon continued upward pull on the well string tensions the entire length of the string. When the entire string has been subjected to the desired tensile strain, the spring I2 yields suiilciently to disengage the bore Il from the latch heads Illa and at the same time engage the shoulder IBa by the shoulder II as shown at Fig. 3, and the latch heads I 0a being thus disengaged from the groove I9 as a result of their transverse alinement with the enlarged bore 20, the compressed spring I drives the released mandrel i upwardly so that the hammer l strikes' a jarring blowl against the anvil 'I as shown at Fig. 4, with thejarring blow transmitted to the lower portion 3a of the well string through the elements I-2, and the engagement of the shoulder I1 with the shoulder I6 maintaining the entire well string under peak tensile strain during delivery of this jarring'blow.

I-f the stuck element is not released by the first jarring blow, the string 3 is lowered so as to return the parts to the position shown at Figs. 1 and 2, the mandrel 5 and the latches Il being thus relatively telescoped while the latches slide through the bore I8, until the latch heads lIla ride outwardly on tapering surface 22, as is permitted by a counterbore I8a at the end of bore. Il, and the latch heads then reseat in groove I9 for locking the mandrel against sliding movement. The jar may then be again actuated. and the operation may be repeated until the stuck element has been jarred loose.

1., In a jar which is adapted to have tensile strain exerted thereon, an anvil, a hammer spaced -from the anvil, means for releasably holding the hammer against movement toward the anvil, a spring adapted for compression while the hammer is'so held, the compressed spring being adapted to drive the released hammer against the anvil for delivering a jarring blow, a spring yieldable responsive to tensile strain on the jar for releasing the holding means, and means for maintaining lthe jar under tensile strain during delivery of the jarring blow.

2. In a jar, an anvil, a hammer, a spring, means actuated by upward strain exerted thereon for deforming the spring so that upon release ofthe deforming stress the spring operates the hammer to strike the anvil a jarring blow, a second spring, meansl actuated by the aforementioned upward strain for maintaining deforming stress on the second spring, the second spring being yieldable responsive to the aforementioned upward strain for releasing the deforming stress on the rst spring, and means for maintaining the jar under tensile strain during delivery of the jarring blow.

3. In a jar, an anvil, a hammer, a spring, means actuated by longitudinal stress exerted thereon for deforming the spring, a second spring, the second spring being vyieldable responsive to said aforementioned longitudinal stress for releasingA the deforming stress on the iirst spring so that said iirst spring operates the hammer to strike the anvil a jarring blow, and means for maintaining the jar under tensile strain during delivery of the jarring blow.

4. In a jar, an anvil, a hammer, a spring, means actuated by upward strain exerted thereon for deforming the spring so that upon release of the deforming stress the spring operates the hammer to strike the anvil a jarring blow, means for holding against lrelease of said deforming stress, a second spring yieldable under tensile strain exerted on the jar for releasing the holding means to permit striking movement of the hammer, and means for maintaining the jar under tensile strain during delivery of the jarring blow.

5. In a jar, an anvil, a hammer, a spring, means actuated'by upward strain exerted thereon for deforming the spring so that upon release of the deforming-stress the spring operates the hammer to strike the anvil a jarring blow, means for holding against release of said deforming stress, a second spring, means actuated by tensile strain .exerted on the jar, for maintaining deforming stress on the second spring, the second spring being yieldable responsive to said tensile strain for 6. In a jar adapted for incorporation in a well string, a sectional body, an anvil, a hammer, a spring, means actuated by upward strain exerted thereon for deforming the spring so that upon release of the deforming stress the spring operates the hammer to strike the anvil a jarring blow, means for holding against release of said deforming stress, a second 'spring between the sections of the body, means actuated by upward strain exerted on the well string for exerting de, forming stress on the second spring, the second spring being yieldable responsive to said upward strain for releasing the holding means to permit striking movement of the hammer, and means for maintaining the sectional body under tensile strain during delivery of the jarring blow.

- '1. In a jar, an anvil, a hammer, a spring,means actuated by upward strain exerted thereon for deforming the spring so that upon release of the deforming stress the spring operates the hammer to strike the anvil a jarring blow, means for holding against release of said deforming stress, a y

second spring, means actuated by upward strain on the jar for exerting deforming stress on the second spring, the second spring being yieldable responsible to said deforming stress for releasing the holding means, and means for maintaining the jar under tensile strain during delivery of the jarring blow.

MILLARD S. BLACK. 

